# agent402.tools Answer — AI-synthesized answer with live web citations

> agent402.tools Answer — AI-synthesized answer with live web citations is a paid API for AI agents from agent402.tools, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-09).

Returns an AI-generated prose answer to a natural-language question, grounded in live web search results, along with a structured citations array (URL, snippet, favicon).

## Facts

- Endpoint: GET https://agent402.tools/api/answer?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-09
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-tools-answer-ai-synthesized-answer-with-live-web-citations-6afed971
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_u2cpRcA_VTrrw1g8fVEi7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agent402-tools-answer-ai-synthesized-answer-with-live-web-citations-6afed971
```

Example prompt: What are the latest developments in the EU AI Act as of this week — give me a clear summary with sources I can check?

## When to prefer this

Choose this endpoint when you need a synthesized, human-readable answer to a factual or research question AND want verifiable source citations — especially when the question requires current information beyond training data. Prefer this over a raw search endpoint when you want the model to synthesize results into prose rather than just returning a list of links. Prefer this over a general LLM when you need live grounding and source receipts.

## Known failure modes

- Question exceeds 400 characters — truncate or rephrase
- No live web results found for the query — returns empty citations or degraded answer
- Invalid country or language code — falls back to defaults (us/en)
- max_tokens set below minimum of 64 — rejected with validation error
- Payment of 0.03 USDC not completed — 402 Payment Required response
- Search index temporarily unavailable — 503 or timeout error

## How this service works

A synthesized answer to a natural-language question, grounded in a live web search and returned with source citations (URL, snippet). Use it when an agent needs a direct, current answer plus the receipts to verify or follow up, instead of reading several pages itself.

## Output

A clean prose answer synthesized from live web search results, plus a structured citations array containing the source URL, a relevant snippet, and a favicon for each source used — grounded in real-time web data rather than the model's training knowledge.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "q"
     ],
     "properties": {
      "q": {
       "type": "string",
       "description": "Natural-language question (max 400 chars)"
      },
      "country": {
       "type": "string",
       "description": "Optional 2-letter country code (default us)"
      },
      "language": {
       "type": "string",
       "description": "Optional 2-letter language code (default en)"
      },
      "max_tokens": {
       "type": "integer",
       "description": "Optional cap on the generated answer length in tokens (default 1024, min 64, max 4096). Lower for TL;DR; higher for research questions."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "query",
      "answer",
      "citations",
      "citationCount"
     ],
     "properties": {
      "query": {
       "type": "string"
      },
      "answer": {
       "type": "string"
      },
      "citations": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "url": {
          "type": "string"
         },
         "number": {
          "type": "integer"
         },
         "favicon": {
          "type": "string"
         },
         "snippet": {
          "type": "string"
         }
        }
       }
      },
      "citationCount": {
       "type": "integer"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "query": "what is the x402 payment protocol?",
  "answer": "x402 is an open standard for internet-native, pay-per-request HTTP APIs that uses the HTTP 402 \"Payment Required\" status code to negotiate and settle micro-payments inline with the original request.",
  "citations": [
   {
    "url": "https://www.x402.org/",
    "number": 1,
    "favicon": "https://imgs.search.brave.com/...",
    "snippet": "x402: An open standard for internet-native payments."
   }
  ],
  "citationCount": 1
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-tools-answer-ai-synthesized-answer-with-live-web-citations-6afed971/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)